StarCraft II: Heart of the Swarm is an expansion pack to the military science fiction real-time strategy game StarCraft II: Wings of Liberty by Blizzard Entertainment. Heart of the Swarm is the second part of a planned

StarCraft II trilogy, with part three titled Legacy of the Void.[3] The expansion includes additional units and multiplayer

changes from Wings of Liberty, as well as a continuing

campaign focusing on the Zerg race, following Sarah Kerrigan in her effort to regain control of the swarm and exact her revenge on the Terran Dominion's emperor,

Arcturus Mengsk. Gameplay The game has 20 missions in the campaign (plus 7 evolution

missions which allows the player to upgrade its units), and continues the story from Wings of Liberty.[4] The player plays from the perspective of Sarah Kerrigan, recently returned to her human form by Jim Raynor.[5] Similar to Wings of Liberty, the briefing room is replaced with an

interactive exploration of the Leviathan, an enormous zerg

breed which functions as a Bioship. Kerrigan and her allies are located in the nerve center, she has a personal chamber

for altering her abilities, and there is an evolution pit where

she can upgrade her units and perform evolution missions

with the evolution master Abathur. At Blizzard's 2011 BlizzCon conference, it was revealed

that Heart of the Swarm will feature 7 new multiplayer units, while removing 3 units[6] and changing the abilities of existing units and buildings. The exact modifications have

since changed. In a blog post, game director Dustin Browder explained the current status of the units.